#VU19075 Integer underflow in Windows and Windows Server - CVE-2019-1093

Vulnerability identifier: #VU19075

Vulnerability risk: High

CVSSv4.0: 5.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2019-1093

CWE-ID: CWE-191

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Windows
Operating systems & Components / Operating system
Windows Server
Operating systems & Components / Operating system

Vendor: Microsoft

Description

The vulnerability allows a remote attacker to execute arbitrary code on the affected system.

The vulnerability exists due to an integer underflow during the parsing of font files in the DirectWrite library. A remote attacker can use a specially crafted document or a webpage, trick the victim into opening it, trigger an integer underflow and execute arbitrary code on the system.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Windows: 7, 8.1 RT - 8.1, 10 1607 10.0.14393.10, 10 1703 10.0.15063.138, 10 1709 10.0.16299.19, 10 1803 10.0.17134.48, 10 1809 10.0.17763.1, 10 1903 10.0.18362.116, 10

Windows Server: 2008 R2 - 2008, 2012 R2 - 2012, 2016 10.0.14393.10, 2019 10.0.17763.1 - 2019 1903

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External links
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-1093
https://www.zerodayinitiative.com/advisories/ZDI-19-654/

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.